The men, who appear to be smiling, are said to be the three bombers. According to a government official, they hail from Russia, Uzbekistan and Kyrgyzstan.

Interfax news agency says reports one of the attackers is from Dagestan, on the Chechen border, have been denied by Russian police. However, the Russian Interior Ministry has said it is looking into the claim.

The pro-government Yeni Safak newspaper suggested Chechen involvement in the attack on the Istanbul transport hub. The Turkish daily reported the organiser was Akhmed Chatayev, a male of Chechen origin.

A United Nations sanctions list names him as an ISIL leader charged with training Russian-speaking militants. Chatayev is listed as being wanted by Russian authorities.

Turkish officials have not confirmed his involvement.

ISIL link?

No person or group has admitted responsibility, however analysts and US counter-terrorism experts agree both the target and method of the attack bear the hallmarks of ISIL. Earlier in 2016, the jihadist group bombed an airport and metro in Brussels and has been blamed for a number of attacks in Turkey in the past 12 months. The militants also claimed responsibility for the deadly Paris attacks in November 2015.

US Homeland Security Secretary Jeh Johnson was among officials making the connection with ISIL. He also confirmed that one American citizen was injured in the attack.

Turkey is part of the US-led coalition fighting ISIL and currently allows its Incirlik airbase to be used for air raids. However, it has not actively taken part in bombing raids. Analysts suggest the Ataturk attack could push Ankara to take stronger action against the jihadists.

Raids and arrests

City-wide raids on 16 addresses in Istanbul have seen at least 13 people arrested in connection with the Ataturk incident, including three foreigners, Ala says.

Death toll

At least 44 people died in the attack on Europe’s third-busiest airport – 19 of whom were foreign nationals or held dual nationality – making it the deadliest in a series of suicide bombings in Turkey this year.

The toll is expected to rise. Dozens of the more than 230 people injured are in critical condition in hospital.

What happened?

Three bombs were detonated on Tuesday evening (June 28) at the International terminal of Istanbul’s biggest airport. The first was detonated in the Arrivals area of the ground floor; the second at the entrance to Departures, on the first floor; and the third in the car park.

Turkish Prime Minister Binali Yildirim later said three men had intended to pass through the security checkpoint, but on seeing the controls “took their weapons out of their suitcases and opened fire at random at the security check.”

The third explosion was the most harmful to the surrounding people. The suspect is said to have waited outside the terminal and detonated his explosives as people fled.